Steam-engine indicator.



No. 655,857. Patented Aug. 14, |900.

L. n. DURAN a A. TAGGABT.

STEAM ENGINE INDICATOR.

(Anvlication led Mar. 20. 1900.) (No Model.)

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UNITED STATES PATENT FFICE,

Lewis no1-mar Donau AND ARTHUR, frneenar, or eLAseow, soorLANij;

Veran?ivi-ENGINE lNdlcAron.

SPECIFICATION forming; part f Letters Patent No. 655,857, dated August 14, 190e. Application nea naar 20,1900'. serrant. 9,435. cumin.)

To all whom it may concern,.-

le it known that we,LEWIs RoBEn'rDonAN, residing at Gallowflat House, Rutherglen, Glasgow, and ARTHUR Tnecnnr, residing at 30 Sutherland Terrace, Glasgow, Scotland, citizens ef the United Kingdom of Great Britain and Ireland, have invented certain new and useful Improvements in Steam-Engine Indicators, (for which application for patent has been made in Great Britain, No. 18,227, dated September 9, 1899,) of which the following is a specification. y

This invention relates to improvements in indicators for steam or other engines, and has for its objects to facilitate the changing of the diagram-cards, especially when running at high speed, and also to provide more efficient means for multiplying the motion imparted to the recording-pencil. Y

The invention is illustrated by the accompanying drawings'.

Figure 1 is a verticalY section of our improved indicator, and Fig. 2 a plan of the samel with the cylinder-cover and parallel motion removed.

In accordance with our invention the paper-drum A and the cord-drum B are separate from eachother and are mounted upon the vcentral supporting-spindle C in the same relative positions to those of existing indicators, each being under the influence of an independent springAB', respectively. The corddrum B is rotated in the usual way, and the paperedrum A is driven therefrom by a pin or stud E, arranged in the path of a pin or stud F on the cord-drum B. In order that a new card may be placed around the paperdrum A while the cordedrum B is connected to the engine, the lower end of the papendrum A is provided with teeth A to receive a detent in the usual way; but in place of employing an ordinary detent, which causes the paper-drum A to receive a .shock when the stop of the cord-drum B lifts it off at each stroke, and thus adds to the difiiculty of getting on a card, we may employ adetent or pawl G, acted upon by a flat or other spring H, which normallyholds it out of action, and centered at G on a ring sleeve or collar I, capable of being rotated or partially rotated around the outside of the cylinder K by a knob or handle J to bring itr into action. In order to ar-1 lrestl the paper-drum A, the aforementioned collar or sleeve I is rotated to the position shown by the dotted lines, Fig. 2, causing the detent or pawl G to engage with one of the teeth A and by its continued rotation in a direction opposite to that exerted by the springs removes the pin E of the paper-drum out of the reach of the cord-drum pin F. The sleeve I may, as shown, be retained in position by a horseshoe-shaped ring M, situated above the sleeve I and entering an annular groove K in the'cylinder K, which latter may also be formed with stops or projections K2 for regulating the extent of travel of the sleeve I. ToY restart the paper-drum A, the sleeve I is returned to the position indicated in full lines, Fig. 2, which shows the detent G just leaving the teeth A'. This latter movement insures the drum A starting without shock, as the detent G is not released from the teeth A of the paper-drum A until the tension of the latters spring A is being borne by the pin F of the cord-drum B. Further, in order that the motion imparted to the recordingpencil may be more efciently multiplied, we pivot the pencil-carrying arm R to a short link O, which in turn is pivoted or hinged to a standard or stationary arm P, mounted upon any convenient part of theindicator. A pair of toggles or hinged links Q R are pivoted, respectively, to the before-mentioned standard I) and to a point N upon the pencil-carrying arm, the arrangement resembling a lazytongs and being such that when one of the toggles Q is subjected to a very slight motion from the piston S through the piston-rod S vand connecting-link T a very considerable motion is given through the toggle It to the pencil-arm N, thus producing a diagram of greater exactitude. One of the toggles, preferably the toggle R, may be fitted with a pin or projection R', arranged to work in a guide 'l of suitable form for the purpose of securing a perfectly-vertical motion.

With this indicator also we may attach the end of the springV to. thepiston S within the cylinder K by passing the end thereof through an aperture formed in a stud W, attached to the piston S and screwed into the end of the piston-rod S, thus lightening the weight of IOO the moving parts. The end of the spring N may be retained in position by brazing or otherwise.

Having now described the invention, what We claim, and desire to secure by Letters Patl. An indicator' for steam or other engines comprising a oord-drum, an independent paper-carrying drum having a series of teeth thereon and mounted upon the same spindle as the cord-drum, springs controlling these drums,a peneil-carryin g arm arranged in proX- imity to the paper-drum and forming one element of a parallel motion consisting of a link jointed to said pencil-arm and to a stationary standard, a pair of toggle-links connected to the standard and to the pencil-arm, and also connected by a short link to the pistonrod and a detent or paWl centered on a movable collar or sleeve capable of being rotated to bring said detent into engagement with a series of teeth on the paper-drum, substan tially as and for the purpose set forth.

2. In an indicator for steam or other engines, the combination with a paper-drum having a series of teeth thereon, and mounted on a central spindle, of a spring for controlling said drum, a stud or pin secured in the paper-drum, a eorddrum independent of the paper-drum, a spring for controlling the cord-drum and a pin or stud therein in enn gagement with the paper-drum, so that the paper and cord drums normally rotate together, a detent or paWl adapted to engage the teeth on the paper-drum, a movable collar or sleeve on which said detent or pavvl is centered capable of being rotated to bring the detent into engagement with the teeth upon the paper-carrying drum, to turn said drum to such a position that its stud is held out ot' the path of the pin on the oord-drum, and a spring bearing on said paWl and normally holding it out of engagement With the teeth, substantially as and for the purpose set forth.

In an indicator for steam or other engines, the combination With a rotatingr paperdrum of a parallel motion consisting of apencil-carrying arm, a link connecting said pencil-arm to a stationary standard, a pair of toggle-links connected to said standard and to the penoil-arm, a guide-pin on one ol the toggle-links, a stationary guide in which said pin moves, and a short link connected to the other toggle-link and to the piston-rod, suhstantially as and for the purpose set forth.

4. In an indicator for steam or other eugines, the combination with a paper-drum having a series of teeth thereon, of a detent or pawl, a movable collar or sleeve on which said detent or pawl is centered capable of being rotated to bring` the detent into engage ment with the teeth upon the paper-carrying drum, and a spring bearing on said pawl and normally holding it out of engagement With the teeth, substantially as and for the purpose set forth.

In witness whereof we have hereunto set our hands in presence of two Witnesses.

LEVIS ROBERT DORAN. ARTHUR TAGGART.

Witnesses:

WALLACE FAIRWEATHER, JNO. ARMSTRONG, J r. 

